The Duke of Edinburgh is expected to take it easy today as he celebrates his 91st birthday just a day after leaving hospital.
Philip was discharged from King Edward VII Hospital in central London yesterday after spending five days there having treatment for a bladder infection.
A spokesman for Buckingham Palace would only say that he would be spending the day "privately".
He said yesterday: "The Duke of Edinburgh continues to make a good recovery and he will continue his convalescence at home."
The Duke, who is usually known for being fighting fit for his age, previously suffered a health scare over Christmas when he received treatment for a blocked coronary artery.
Then the Duke was back carrying out engagements within a matter of weeks and in his grandson Prince Harry said the operation had given him "a new spurt of life".
Yesterday he was already showing signs of his acerbic wit by answering one reporter who asked him if he was feeling better: "Well, I wouldn't be coming out if I wasn't."
Philip received a number of visitors during his hospital stay, including his grandsons, the Duke of Cambridge and Prince Harry who paid a short, private visit on Friday.
William visited his grandfather while on leave from his RAF Search and Rescue duties.
Harry, meanwhile, was spending the week since the Diamond Jubilee celebrations on pre-deployment training at Wattisham in Suffolk.
The Queen, the Duke of York, the Earl and Countess of Wessex and their children, Louise and James also went to see him during his stay.
Philip has been planning to celebrate his birthday privately and is not due to attend his next scheduled engagement until Tuesday, when the Queen hosts a garden party at the Sandringham Estate to mark her Diamond Jubilee.
It is hoped her husband will be by her side at her Norfolk retreat if he is feeling strong enough following his discharge from hospital.
It is also hoped he will be able to accompany her to the East Midlands on Wednesday for a two-day visit as part of the Queen's Jubilee tour of the UK.
Philip's admission to hospital meant he was forced to miss some of the Jubilee celebrations this week.
He spent Sunday braving the elements for the Thames River Pageant, which doctors suggested might have exacerbated his condition if he did not make enough visits to the toilet.
The King's Troop Royal Horse Artillery will fire a salute in London's Hyde Park to mark Philip's birthday.
The salute is fired every year to herald the occasion and the event is open to the public but not customarily attended by members of the Royal Family.